In the field of well construction in the oil and gas industry, it is sometimes necessary to drill a second well to provide a conduit for establishing hydraulic communication with a first well. This may be necessary, for example, when it is required to kill or intervene with the first well, especially in scenarios where surface intervention on the first well is impossible or impractical. Accordingly, the second well is commonly referred to as a “relief well,” while the first well is referred to as a “target well.”
The relief well is typically drilled from the Earth's surface as a straight borehole down to a planned kick-off point, where it is deviated toward the target well using conventional directional drilling technology. Drilling then is continued until the relief well intercepts the target well, usually at a shallow angle, and thereby establishes hydraulic communication between the two wells. High-density fluids can then be pumped into the target well from the relief well to generate hydrostatic pressure within the target well that stops well fluids from advancing to the surface. This process is commonly referred to as “killing” the target well.
In order to accurately intercept the target well, wellbore ranging techniques are employed. Traditional wellbore ranging techniques and/or technologies concentrate on the ability to detect a remnant ferromagnetic field from the target well or an induced magnetic field by some means from either the relief well or the target well. This requires some sort of metal casing or piping to be positioned within the target well to help facilitate the magnetic field. These wellbore ranging techniques, however, do not work in open-hole wellbores having no metal casing or piping positioned therein.